WhatsApp and Telegram have both billed themselves as secure alternatives to phone, text or email correspondence. For the most part, that’s true, the two are end-to-end (e2e) encrypted by default and because of this, your conversations are much harder to monitor by outsiders.

But, sometimes it’s not the application that leads to security vulnerabilities, it’s something else entirely. In this case, that “something else” is Signaling System 7 (SS7), a global network of carriers that acts as a central hub to connect the world — we’ve talked about it before.